Fluid proportioning apparatus



June 24, 1958 D. A. CAMPBELL EI'AL 2,840,153

FLUID PROPORTIONING APPARATUS r Filed April 3, 1957 4 Sheets-Sheet 1 INVENTORS DONALD A. CAMPBELL 44 J KVMARGASON WW ATTY June 24, 1958 D. A. CAMPBELL ETAL 2,840,153

FLUID PROPORTIONING APPARATUS Filed April 3, 1957 4 Sheets-Sheet 2 I I 1, a,

INvENToRs DONALD A. CAMPBELL JACK V. MAEGASON "a ATTY.

June 24, 1958 D. A. CAMPBELL ETAL 2,840,153

FLUID PROPORTIONING APPARATUS Filed April 3, 1957 4 Sheets-Sheet 4 INVENTORS DONALD A. CAMPBELL JACK V. MARGASON ATTY.

United States Patent ice FLUID PROPORTIONIN G APPARATUS Donald A. Campbell and Jack V. Margason, Rockford,

Ill., assignors to Eclipse Fuel Engineering Co., Rockford, IlL, a corporation of Illinois The improved fluid proportioning apparatus comprising the present invention has been designed for use primarily in connection with the proportioning and mixing, or the proportioning without mixing, of the gaseous constituents of a combustible mixture, for example, fuel gas and air, the mixture being designed for use in industrial furnaces, ovens, boilers and the like such as may be encountered in metal heat-treating, melting, annealing and similar operations, as well as in steam generating, hot water heating and other processes too numerous to mention. The invention is, however, capable of other uses and the same may, if desired, with suitable modification, be employed for the proportioning, with or without mixing, of a liquid and a gas, or of tWo liquids regardless of their nature or the use to which they may ultimately be put. Irrespective, however, of the particular use for which the invention may be employed, the es sential features thereof are at all times preserved.

The proper control of the proportioning of gaseous fuel and air for the purpose of obtaining a combustible 1 fuel-air mixture which will conform to all phases of furnace operation and produce a uniformly efficient controlled furnace atmosphere at any given instant presents numerous factors which must be reckoned with and, principal among these are changes in internal furnace pressure caused by an increase or a decrease in the firing rate of the furnace burners, changes in frictional resistance offered to the gas or air manifold piping or other passages due to changes in the rate of flow of these gaseous media within the same, and changes in the pressure at which either the air or the gas, or both, are supplied to the proportioning device. These factors, for reasons that are well known and which need not be discussed in detail herein, contribute toward erratic performance of the burner system in the absence of any means for adjusting the fuel-air ratio of the proportioning device to produce the proper combustible mixture which will produce optimum results and give the desired character of flame in both the low and high firing range of the burner. In some instances, the effectiveness of the air inlet to the proportioning device will be reduced when the furnace is operating at maximum firing rate and, with conventional proportioning devices, when an adjustment is made to increase the efiectiveness of the air inlet at the high firing range, the effectiveness of the adjustment is not prevalent when the firing rate is reduced. In most proportioning apparatus heretofore devised for the proportioning of gaseous fuel and air, Wherever provision is made for varying the areas of the fuel and air inlets, a predetermined and fixed fuel-air ratio is maintained throughout the entire range of burner operation. In a few such proportioning devices provision is made for varying the fuel-air ratio to increase burner efficiency at high firing rates but in these instances the rate of change in the fuel ratio is invariably constant with one factor increasing with respect to the other according to some form of arithmetical progression and l atented June 24, 1958 can be regarded merely as a compromise and incapable of satisfying the requirements of widely differing installations.

The present invention is designed as an'irnprovement over existing. proportioning devices in that it provides a novel means whereby practically all variables: which are encountered in any selected burner installationmay be compensated for so that the optimum fuel-air ratio may be obtained for any point in the firing range of burner operation. This being among the principal objects of the present invention, it is a further object to provide such a burner which is capable of initial adjustment by empirical methods to accommodate the fuel-air requirements of any given installation and which, after such adjustments have once been made, will be effective to control the operation of that particular installation with maximum efiiciency indefinitely.

It is a further object of the invention to provide a proportioning device of the character briefly outlined above which in one form thereof is capable of use as a mixing valve'to effect a complete mixture of combustible gas and air in predetermined quantities, commensurate with the demands of the burner installation, withina mixing chamber contained wholly within the confines of the device for subsequent conduction in a mixed state to the burner, and which, in a' slightly modified form thereof utilizing most of the same identical structure, is capable of use solely as a proportioning device for supplying separate quantities of gas and air to a remote mixing burner or the like.

Yet another object of the invention is to provide such a proportioningdevice in which the fuel-air ratio for any given installation may be changed at will throughout the entire range of burner operation in accordance with a pattern of operation by effecting certain initial adjustments and, thereafter, the burner operation controlled by the device merely by manipulation of a single operating handle or lever.

The provision of a proportioning device which is relatively simple in its construction, consisting as it does of but three essential main castings operatively assembled upon one another, and which, therefore, may be manufactured at a relatively low cost; one which is possessed of a minimum number of moving parts and which, therefore, is unlikely to get out of order; one which is capable of being readily disassembled feassembled for purposes of inspection, replacement of parts or repair; one which is rugged and durable and which, therefore, is possessed of a relatively long" life; one which lends itself to automatic operation in' place of manual control if desired; and one which otherwise is well adapted to perform the services required of it", are further desirable features which have been borne in mind in the production and development of the present invention.

Numerous other objects and advantages of the invention, not at this time enumerated, will become more readily apparent as the nature of the invention is better understood.

In the accompanying four sheets of drawings forming a part of this specification, two embodiments of the invention have been shown.

In these drawings:

Fig. l is a front elevational view of a fuel constituent proportioning device constructed in accordance with the principles of the present invention. In this view, certain parts have been broken away to more clearly reveal the nature of the invention;

Fig. 2 is a side elevational view of the structure shown in Fig. 1;

, l 1 3 Fig. 3 is a top plan view of the structure shown in Fig. 1;

Fig. 4 is a sectional view taken substantially along the; of'Fig. 2; i

.Fig.-5 :a fragmentary side elevational view of a portion of the structure shown in Fig. 4;

. .Fig. 'a;90. development viewtaken substantially along the curved line 6-6 of Fig. 4 in the direction indevice; and

. Fig. 10 is a sectional View taken substantially along the line 1010 of Fig. 9.,

'Referring now to the drawings in detail, the fuel proportioning device comprisingthe' present invention is capable of useas a mixing valve to eifect a complete mixture of combustible gas and air in predetermined quantities within the confines of the device for subsequent conduction in a mixed state to the burner or burners associated with an industrial furnace, boiler, heater, oven or the like, and it is also capable, with but slight modification, of use solely as a proportioning device whereby predetermined quantities of gas and air may be regulablysupplied, each isolated from the other, to the gas and air entrance ports respectively of a mixing burner orburners where they are then commingled prior to ignition at the burner nozzle. Irrespective, however, of the paticular use to which the invention may be put, the essential features thereof are at all time preserved. The first mentioned use of the device, i. e. as a gas-air mixing apparatus, has been illustrated in Figs. 1 to 8, inclusive, of the drawings while the use of the same solely as a fuelat proportioning device has been illustrated in Figs. 9 and 10. r a It is to be distinctly understood that the term gas and fuel as used herein are inclusive of liquid fuel such-as liquefied gas, as well as as oil, both of the many kinds presently known and widely used. These terms have been used more or less indiscriminately but are intended to include gaseous or liquid fluids which, when combined with oxygen or air, produce a mixture which will support combustion. During the description of the device and of its operation, the term combustible mixture as employed herein refers to the combined volumes .of gas and air intended to be used for combustion purposes after the same have been discharged from the device. a

Referring now to Figs. 1 and 7, the fuel-air proportioning device involves in its general organization three principal metal castings including an outer stationary manifold casting 10, an inner movable cut-off and shutter casting12, and an end casting 14. Briefly, and as will be described in more detail subsequently, the air .constituent of. the combustible mixture is adapted to pass axially through the assembled device from right to left as viewed in Fig. 7 from an air inlet 16 provided in the end casting 14 to a gas and air discharge outlet 18 provided in the manifold casting 10. The inner cut-off and shutter casting 12 is nested within and concentric with the manifold casting 10 and thus, the air passing through the casting 10 also passes axially through the casting 12, entering the latter through a shutter controlled air inlet 20 and leaves the same through an air discharge outlet 22 leading to a mixing chamber 24 having the, previously mentioned, air outlet 18 associated therewith. Gas enters the assembly through a gas inlet 26 (see also Fig. 4) which extends tangentially inwardly of an arcuate gas entry chamber 28 and from thence it may pass radially inwardly through a series of individually regulated or valve-controlled gas inlet ports 30 in the casting 10 and through an encompassing arcuate cut-off slot 32 in the casting 12 to an annular gas outlet chamber 34 from whence it may pass axially outwardly and into the mixing chamber 24 through a gas discharge opening in the form of an annular slot 36 provided in the casting 12. The cut-off slot 32 is shiftable upon turning movement of the casting 12 within the casting 10 between a'position wherein it is out of register with all but one of the inlet ports 30 to a position wherein it encompasses and is in register with all of these ports, the leading edge of the slot sequentially uncovering the ports as it moves in one direction to progressively admit more gas into the gas outlet chamber 34 and sequentially covering these ports as it moves in the other direction to decrease the amount of gas so admitted. Simultaneously with the regulation of gas flow during turning movement of the casting 12, the admission of air into the device through the air inlet 16 is regulated by a shutter mechanism 38 having cooperating parts on the castings 12 and 14, respectively, the arrangementin general being such that as the flow of gas into the mixing chamber 24 is increased, the flow of air into the chamber for mixing purposes is likewise increased, the specific proportions involved being, of course, a function of the specific setting of the various valve controlled ports 30.

Referring now to Figs. 4, 6 and 7, the outer manifold casting 10 is generally of cylindrical design and includes a hollow tubular body or shell 40 having circular attachment flanges 42 and 44 at its'inlet and its outlet ends, respectively, and formedwith an internal bore 46 and an enlarged counterbore 48 defined by a radial shoulder 50 therebetween. The casting 10 is formed with an external enlargement in the form of an arcuate wall 52 of approximately 90 extent, this wall, in combination with short radially projecting end walls 54 and 56 and a short radial longitudinally extending wall 58, and with the adjacent arcuate outer surface 60 of the shell 40, defining the previously mentioned gas entry chamber 28. As best seen'in Fig. 4, one side of the chamber 40 is open and communicates with the gas inlet 26.

; The various gas inlet ports 30 which are formed in the shell 40 are arranged in two rows with the ports of one the staggering of the ports will be resorted to when circumferential space limitations require that certain of the ports be offset with respect to other ports. The arcuate outer wall 52 is formed wtih a raised or thickened portion 62 (Figs. 4 to 7, inclusive) of serpentine configuration and through which there extends a series of threaded b0res'64, each bore being in radial alignment with one of the gas inlet ports 30 provided in the shell 40. An enlarged core opening 66 provided for manufacturing facility at the end of the thickened portion 62 is adapted to be closed by means of a closure plug 68. Each bore 64 receives therein a valve member 70 having a cylindrical valve body 72 which is threaded through the bore 64. The inner end of each valve body is formed with a conical valve 'proper 74 designed for cooperation with the port 30 with which it is aligned and the other end of the body is slotted as at 76 to facilitate turning movement of the valve body within the bore 64 for adjusting purposes. I A lock nut 80 serves to clamp each valve body 72 in any selected position of adjustment.

The end casting 14 is in the form of a shallow generally cup-shaped member having a flat bottom wall or shutter plate 82 (Figs. 7 and 8) provided with a pair of substantially triangular shutter openings 84 formed therein and arranged in diametrical opposition to each other. The casting 14 is provided with a thickened rim portion 86 having formed therein an annular groove 90 which is opensided throughout an angle of slightly more than 90 in the upper regions of the casting as indicated at 92 in Fig. 1. The casting 14 is also formed with a continuous radial flange 94 having an offset portion 95 of approximately 90, the groove 90 and offset 95 collectively, being substantially coextensive around the peripheral regions of the casting. A series of spaced fastening screws 96 pass through the arcuate flange 94 and extend into the flange 42 on the casting and serve to fixedly maintain the two castings 10 and 14 in their assembled relationship. A series of screws 98 are threadedly received in holes 1% formed in the rim portion 86 and serve to removably retain a grille 162 in position over the air inlet opening 16 of the end casting 14. The grille 1112 may assume various forms but in the illustrated form of the invention it is shown as being of one-piece construction having a circular rim 104 and horizontal curved grille bars 1116.

The inner cut-off and shutter casting 12 is in the form of a hollow annular ring which is generally triangular in radial cross section as best seen in Fig. 7. The casting 12 is provided with a generally cylindrical outer wall 108,

this being the wall in which the previously mentioned cutoff slot 32 is formed. The wall 108 is nested within the cylindrical counterbore 48 of the casting 10 so that the casting 12 as a whole is rotatable within the casting 10. A frusto-conical inner wall 11 merges with the outer wall 108 in the forward or air inlet regions of the casting and the forward end of the ring-like casting is provided with a radial wall or shutter plate 112 having a pair of generally triangular shutter openings 114 formed therein designed for cooperation with the shutter openings 84 in admitting air to the interior of the casting 12, the two shutter openings, when in partial or full register with each other, affording the previously mentioned air inlet 21) for the casting 12. The inner and outer walls 110 and 108,. respectively, are connected together by a radial wall 115, the three walls 108, 119 and 115 defining the inner gas chamber 34. The cut-off slot 32 (see also Fig. 4) is of such arcuate extent that it is capable of encompassing all of the radial ports formed in the shell when the casting 12 is moved in a counterclockwise direction as viewed in Fig. 4 to one extreme position thereof. At such time the shutter openings 84 and 114 are in full register and maximum air flow into the casting 12 is obtained. When the casting 12 is moved in the opposite direction to its other extreme position, the trailing edge of the slot 32 assumes a position wherein the first port in theseries is uncovered. Under such conditions the shutter openings 84 and 114 are out of register with each other and air is excluded fromentering the conical bore of the casting 12.

As best seen in Figs. 4 and 7, the outer manifold casting 10 is provided with a bottom outlet opening 116 which, when the proportioning device is used as a mixer is normally closed ,by a threaded plug 118. The opening 116 is designed for partial or full register with an arcuate slot 121} formed in the shell 40 of the casting 12 in any position of the latter. The slot 120 and opening 116 have no function when the device is employed as a mixer and further reference to these openings will be made subsequently when the use of the device as a proportioning apparatus for the independent flow of gas and air to a burner or the like is set forth.

The movements of the inner cut-off shutter casting 12 are manually regulated under the control of an operating handle 122 in the form of a rod or stick having an operating knob 124 at its outer end. The inner end of the rod is formed with a reduced threaded portion 126 (Figs. 7 and 8) which is received in a socket 128 formed in the forward regionof the casting 12 at a point where the same is exposed between the flange 42 and offset rim portion 95 of the castings 12 and 14, respectively. The relieved regions of the flange and rim portion afford, in effect, an

arcuate groove of slightly more than in extent within which the inner end of the rod or handle 122 may operate. It will be understood that for automatic operation of the apparatus a suitable linkage mechanism may be substituted for the handle 122 and operatively connected to a control mechanism of any appropriate character.

A pair of circumferentially adjustable limit stop members 130 having clamping screws 131 associated therewith are capable of being clamped in selected positions adjacent to the ends of the groove 129 and are designed for engagement with the inner regions of the operating handle 122 to limit the extreme positions thereof.

As best seen in Figs. 1 and 2, a removable cover plate 132 of arcuate design and which is U-shape in transverse cross section is removably held inposition over the outer end of the various adjustable valve members 72 by means of a locking screw 133 and one side of the plate 132 is provided with a scale having indicia markings 134 designating the various gas inlet ports 30 which are uncovered by the slot 32 in any selected position of the handle 122. A cotter pin 135 constitutes a hinge connection for the plate 132 whereby it may be swung to an out-of-the-way position to uncover and expose the valve members 72.

In the operation of the above-described apparatus as a mixing device wherein quantities of gas and air are commingled within the mixing chamber 24, the removable grille 192 is applied to the air inlet opening 16 and the gas inlet opening 26 is connected by a suitable gas conduit such as has been shown at to a source of fuel at a constant pressure, as, for example, gas issuing from a suitable pressure regulator (not shown). The discharge outlet 18 is connected by means of a pipe flange 142 to a delivery conduit'144 leading through a suction device (not shown) to a burner or series of burners associated with the furnace or other equipment undergoing firing. The various proportioning gas inlet valve members 72 are individually adjusted so as to vary the volume of fuel admitted to the 'annular gas chamber 34 in the casting 12 during the progressive sweeping movement of the leading edge of the slot 32 across the path provided for it whereby, during such sweeping movement, the various ports 30 are progressively uncovered while at the same time the effective size of the shutter openings 84, 114 are progressively increased. The adjustments of the proportioning valve members 72 may be effected empirically during a test run of a particular installation to establish the necessary modi fication of fuel-air adjustment for the different stages of feed flow of the proportioned combustible mixture whereby the mixture resulting from such proportioning of the gas and air will be of a uniform consistency each time the operating handle 122 is brought to a predetermined setting. With the handle 122 in the upright position wherein it is illustrated in Figs. 1 to 3, inclusive,

the leading edge of the slot 32 will extend slightly beyond the first gas inlet port 30' in the series of ports and the shutter openings 84 and 114 will remain completely out of register with each other so that no air will be admitted to the interior of the device. With this setting of the handle 122 a small quantity of gas, dependingupon the particular setting of the first valve member 72 in the series, will flow from the gas inlet conduit 140, through the gas inlet 26, 90 chamber 23, port 30, slot 32, gas chamber 34 and circular slot 36 to the mixing chamber 24 while at the same time air will be excluded from the mixing chamber. Such a condition is desirable for starting up operations so that a rich fuel mixture will obtain when the burner or burners are initially fired to prevent possible back firing in the system. Upon movement of the operating handle 122 in a counter-clockwise direction as viewed in Fig. 1 to a position wherein the indicia numeral 134 representing position 1 is in register with the handle, the shutter 84 and 114 openings will move into slight partial register to admit a limited quantity of air into the casting 12' and mixing chamber 24 while at the same time the second port 30in the series will be uncovered by the slot 32 so that gas will now flow through both the first and second ports in the series. It

chamber.

, 7 willfbe understood that during previous tests at the furnace or other installation undergoing firing, the valve 72 at position 1 will have been adjusted and stayed by the lock nut 80 at a position wherein the proper amount of gasvolume has been attained with relation to the .volume of air which is admittedat the shutter device 84, 114. f

The operating handle 122 will be progressively advanced through all of the various positions of adjustment of which it is capable and, at each succeeding position thereof,.an additional previously adjusted port 30 in the series of ports will be uncovered by the slot 32 so that, in addition to the combined flow of gas through the previously .uncovered ports, an additional flow of gas through the last uncovered port will be obtained to increase the volume of gas flowing radially inwardly into the gas outlet chamber 34 for subsequent flow into the mixing chamber 24. Each succeeding position of the operating handle will also be reflected by a different relative positioning of the shutter plates 82 and 112 whereby progressively increased shutter opening areas will be attained to increase the flow of air to the mixing It is to be noted that the staggered arrangement of .the ports 30 in the shell 40 of the casting is such that Referring now to Figs. 9, and 10 wherein a slightly modified form of the apparatus is shown with the same being designed for use as a proportioning device whereby predetermined quantities of gas and air may be regulably supplied to a remote mixing burner or the like with each quantity passing through the apparatus isolated from the other, the constituent parts of the apparatus remain substantially the same as in the form of the invention shown in Figs. 1 to 8, inclusive. Thus, to avoid needless repetition of description, similar characters of reference but of a higher order or sequence have been applied to the corresponding parts illustrated in Figs. 1 to 8, inclusive, and Figs. 9 and 10, respectively.

When the mixing features of the invention are to be dispensed with and the device employed solely as a proportioning device for gas and air, the grille 102 is removed and the air inlet 16 is operatively connected to a source of air under constant pressure (not shown), .as, for example, a compressor, blower or the like having constant delivery characteristics, by means of an air conduit 200 having a bolting flange 202 associated therewith and. by means of which it may be attachedto the casting 14, utilizing attachment screws 298'. The threaded plug 118 is removed from the opening 316 at the bottom of the casting 210 and one end of a gas conduit 204 is received in this opening. The gas conduit 204 may extend to a remote mixing burner, as may also the air delivery conduit 344 which is connected to the discharge opening 218.

The outer manifold casting 210 remains identical with the casting 10 and the end casting 214 remains identical with the end casting 14. The inner cut-off and shutter casting 212 however is modified only to the extent that the slot 36 which is machined in the casting 12 is not machinedin the casting 212 so that the latter casting presents an imperforate radial wall 215. With the exception of the differences pointed out above, the mixing valve assembly of Figs. 1 to 8, inclusive, and the proportioning device of Figs. 9 and 10 are identical in their construction.

In the operation of the proportioning device, air under constant pressure from the conduit 200 enters the air inlet,216 and, when the shutter openings 284 and 314 are in partial or full register, this air may pass axially through the apparatus to the air discharge outlet 218. The chamber 224 no longer functions as a mixing chamher since there is no introduction of gas thereinto. Gas enters the gas inlet opening 226 from the gas conduit 340 and flows, as in the other form of the invention, into the gas entry chamber 228, through the various gas inlet ports 230, slot 232, annular gas outlet chamber 234 which is isolated or sealed from the chamber 224, and is discharged from the apparatus through the gas discharge outlet 316 to the gas conduit 204. The operating handle 322 may be manipulated in the manner described in connection with the form of the invention shown in Figs. 1 to 8, inclusive, to effect substantially the same operation of the apparatus with the exception, of course, that the gas and air are not intermingled in the chamber 224 of the casting 210 but are separately conducted to the mixing burner or other mixing device.

In compliance with title 35, U. S. Code, section 22, a preferred form of the invention has been shown in the drawings and described herein, but it should be understood that the invention is not to be limited to the specific disclosure made. For example, while the gas inlet ports 30 and threaded bores 64 are shown as being arranged in'two circumferential rows, it is contemplated that these openings may be arranged in progressive fashion other than that disclosed. A greater number of rows may, if desired, be employed or the openings, instead of being aligned circumferentially may be staggered, offset or otherwise formed. Similarly, while the opening 36 in the wall is shown as being in the form of a circular slot, the provision of one or more perforations or holes in the wall 115 are contemplated. Only insofar as the invention is particularly pointed out is the same to be limited.

Having thus described the invention what we claim as new and desire to secure by Letters Patent is:

1. Proportioning apparatus for effecting a combustible mixture of fuel and air for delivery to a burner or the like comprising an outer casing having a generally cylindrical wall defining an open-ended bore the rear end of which constitutes a discharge outlet for the combustible mixture, a limited circumferential extent of said wall being hollow to define an arcuate gas entry chamber'partially encompassing said bore, there being a gas inlet in communication with said chamber, an inner ring-shaped casing the annular wall of which is hollow to define a gas outlet chamber, said inner casing being closely nested within said bore and capable of limited rotational movement therein in either direction, a shutter plate extending across the forward end of the inner casing and movable with the latter, a cooperating stationary shutter plate extending across the forward open end of said bore, there being a pair of cooperating shutter openings in said shutter plates defining avariable air inlet for the apparatus, there being a series of circumferentially spaced gas inlet ports formed in the cylindrical wall of the outer casing communicating with the gas entry chamber, there being an arcuate slot in the annular wall of said inner casing capable of selective progressive cumulative registry with said ports upon turning movement of the inner casing relative to the outer casing, said inner casing being movable between a retracted position wherein said shutter openings are out ofregistry with each other and said ports are out of registry with said arcuate slot, and an advanced posi tion wherein said shutter openings are in full registry and saidports are all in registry with said slot, there being a gas discharge opening in the hollow wall of said inner casing establishing communication between said discharge outlet and the gas outlet chamber, and an operating handle for said inner casing.-

2. Proportioning apparatus as set forth in claim 1 wherein the hollow wall of said inner ring-shaped casing is generally triangular in radial cross section to provide an outer cylindrical wall section through which said arcuate slot extends, an inner conical wall section and a radial wall section through which said gas discharge opening extends.

3. Proportioning apparatus as set forth in claim 1 wherein the hollow wall of said inner ring-shaped casing is generally triangular in radial cross section to provide an outer cylindrical wall section through which said arcuate slot extends, an inner conical wall section and an annular radial wall section through which said gas discharge opening extends, said latter opening being in the form of a continuous annular slot extending completely around said annular wall section.

4. Proportioning apparatus as set forth in claim 1 including, additionally, individually adjustable means for varying the effective area of each of said gas inlet ports.

5. Proportioning apparatus as set forth in claim 1 wherein the cylindrical wall of the outer casing is formed with a second and adjacent series of circumferentially spaced gas inlet ports communicating with the gas entry chamber and axially displaced from said first series of ports, the ports of the adjacent rows being arranged in circumferentially staggered relationship with respect to each other.

6. Proportioning apparatus as set forth in claim 1 wherein the cylindrical wall of the outer casing is formed with a second and adjacent series of circumferentially spaced gas inlet ports communicating with the gas entry chamber and axially displaced from said first series of ports.

7. Proportioning apparatus as set forth in claim 1 wherein the cylindrical wall of the outer casing is formed with a second series of circumferentially spaced gas inlet ports communicating with the gas entry chamber and axially displaced from said first series of ports, the ports of the two series being arranged in staggered relationship with respect to each other, the arrangement of said ports being such that during movement of said inner casing from its retracted position to its advanced position the leading edge of the slot therein will enter into registry with each succeeding port before completely embracing the next preceding port.

8. Proportioning apparatus as set forth in claim 1 wherein the cylindrical wall of the outer casing is formed with a second series of circumferentially spaced gas inlet ports communicating with the gas entry chamber and axially displaced from said first series of ports, the ports of the two series being arranged in staggered relationship with respect to each other.

9. Proportioning apparatus for eifecting a combustible mixture of fuel and air for delivery to a burner or the like comprising an outer casing having a generally cylindrical wall defining an open-ended bore the rear end of which constitutes a discharge outlet for the combustible mixture, a limited circumferential extent of said wall being hollow to define an arcuate gas entry chamber partially encompassing said bore, there being a gas inlet in communication with said chamber, an inner ringshaped casing the annular wall of which is hollow to define a gas outlet chamber, said inner casing being closely nested within said bore and capable of limited rotational movement therein in either direction, a shutter plate extending across the forward end of the inner casing and movable with the latter, an end casing in the form of a ring secured to the forward end of said outer casing, a shutter plate extending across said ring, there being a pair of cooperating shutter openings in said shutter plates defining a variable air inlet for the apparatus, there being a row of circumferentially spaced gas inlet ports formed in the cylindrical wall of the outer casing communicating with the gas entry chamber, there being an arcuate slot in the annular wall of said inner casing capable of selective progressive cumulative registry with said ports upon turning movement of the inner casing relative to the outer casing, said inner casing being movable between a retracted position wherein said shutter openings are out of registry with each other and said ports are out of registry with said slot, and an advanced position wherein said shutters are in full registry and said ports are all in registry with said slot, there being an opening in the hollow wall of said inner casing establishing communication between said discharge outlet and the gas outlet chamber, and an operating handle secured to and movable bodily with said inner casing and projecting radially outwardly beyond said cylindrical wall of the outer casing.

10. Proportioning apparatus as set forth in claim 9 wherein the hollow wall of said inner ring-shaped casing is generally triangular in radial cross section to provide an outer cylindrical wall section through which said arcuate slot extends, an inner conical wall section, and a radial Wall section through which said gas discharge opening extends.

ll. Proportioning apparatus as set forth in claim 9 wherein said gas entry chamber is defined in part by an outer arcuate wall section and a concentric arcuate inner wall section, said gas inlet ports being provided in the inner arcuate wall section.

12. Proportioning apparatus as set forth in claim 9 wherein said gas entry chamber is defined in part by an outer arcuate wall section and a concentric inner wall section, said gas inlet ports being provided in the inner arcuate wall section, and including additionally, an adjustable valve member for each port projecting through said outer wall section in sealing relationship with respect thereto and having a conical valve surface formed thereon at the inner end thereof designed for cooperation with said port to vary the effective area of the latter.

13. Proportioning apparatus for eifecting a combustible mixture of fuel and air for delivery to a burner or the like comprising an outer casting having a generally cylindrical wall defining an open-ended bore the rear end of which constitutes a discharge outlet for the combustible mixture, a limited circumferential extent of said wall being hollow to define an arcuate gas entry chamber partially encompassing said bore, there being a gas inlet in communication with said chamber, an inner ring-shaped casting the annular wall of which is hollow to define a gas outlet chamber, said inner casing being closely nested within said bore and capable of limited rotational movement therein in either direction, a shutter plate extending across the forward end'of the inner casting and movable with the latter, an end casting in the form of a ring secured to the forward end of said outer casting, a shutter plate extending across said ring, there being a pair of cooperating shutter openings in said shutter plates defining a variable air' inlet for the apparatus, said arcuate gas entry chamber having an inner wall section embodied by said sylindrical' wall of the outer casting, and an outer arcuate wall section concentric with the inner wall section, there being a row of circumferentially spaced gas inlet ports formed in the inner wall section communicating with the gas entry chamber, there being an arcuate slot in the annular wall of said inner casting capable of selective progressive cumulative registry with said ports upon turning movement of the inner casting relative to the outer casting, said inner casting being movable between a retracted position wherein said shutter openings are. out of registry with each other and said ports are out of registry with said slot, and an advanced position wherein said shutter openings are in full registry and said ports are all in registry with said slot, there being a series of threaded holes in the outer arcuate wall section in radial alignment with the ports in said inner arcuate wall section, an adjusting valve threadedly received in each of said threaded holes and cooperating with its respective port to vary the effective port area thereof, there being an opening in the hollow wall of said inner casting establishing communication between said discharge outlet and the ,which'constitutes a discharge outlet for the combustible mixture, a limited circumferential extent of said wall being hollow to define an arcuate gas entry chamber partially encompassing said bore, there being a gas inlet in communication withqsaid chamber, an inner ringshaped casting the annular wall of which is hollow to define a gas outlet chamber, said inner casting being closely nested within said bore and capable of limited rotational movement therein in either direction, a shutter plate extending across the forward end of the inner casting and movable with the latter, an end casting in the form of a ring secured to the forward end of said outer casting, a shutter plate extending across said ring, there being a pair of cooperating shutter openings in said shutter plates defining avariable air inlet for the apparatus, said arcuate gas entry chamber having an inner wall section embodied by said cylindrical wall of the outer casting, an outer arcuate wall section concentric with the inner wall section there being a row of circumferentially spaced gas inlet ports formed in the inner wall section communicating with the gas entry chamber, there being an arcuate slot in the annular wall of said inner casting capable of selective progressive cumulative registry with said ports upon turning movement of the inner casting relative to the outer casting, the hollow wall of said inner casting being generally triangular in radial cross section to provide an outer cylindrical wall section, an inner conical Wall section, and a radial wall section at the rear end thereof, said inner casting being movable between a retracted position wherein said shutter openings are out of registry with each other and said ports are out of registry with said slot, and'an advanced position wherein said shutter openings are in full registry and said ports are all in registry with said slot, there being a series of threaded holes in the outer arcuate wall section in radial alignment with the ports in said inner arcuate wall section, an adjusting valve threadedly received in each of said threaded holes and cooperating with its respective port to vary the effective side of the latter, there being an opening in said radial wall of the inner casting establishing communication between said discharge outlet and the gas outlet chamber, and an operating handle for said inner casting. v

15. Proportioning apparatus as set forth in claim 14 wherein the cylindrical wall of the outer casting is formed with a second row of circumferentially spaced gas inlet ports communicating with the gas entry chamber and axially displaced from said first row of ports, the ports of the two rows may be arranged in staggered relationship with respect to each other, the arrangement of said ports being such that during movement of said inner casting from its retracted position to its advanced position the leading edge of the slot therein will enter into registry with each succeeding port before completely embracing the next preceding port.

16. Proportioning apparatus for effecting a combustible mixture of fuel and air for delivery to a burner or the like comprising an outer casing having a generally cylindrical wall defining an open-ended bore the rear end of which constitutes a discharge outlet for the air, a limited circumferential extent of said wall being hollow to define an arcuate gas entry chamber partially encompassing said bore, there being a gas inlet in communication with said chamber,- an inner ring-shaped casing the annular wall of which is hollow to define a gas outlet chamber, said inner casing being closely nested within said bore and capable of limitedlrotational movement therein in either direction, a shutter plate extending across the for- 12 V Y ward end of the inner casing and movable with the latter, a cooperating stationary shutter plate extending across the forward open end of said bore, there being a pair of cooperating shutter openings in said shutter plates defining a variable air inlet for the apparatus, there being a row. of circumferentially spaced gas inlet ports formed in cylindrical wall of the outer casing communicating with the gas entry chamber, there being an arcuate slot in the annular wall of said inner casing capable of selective wherein said shutter openings are in full registry and said ports are all in registry with said slot, there being a gas discharge opening in the cylindrical wall of said outer casing, there also beinganxopening in said hollow annular wall establishing communication between said gas outlet chamber and the interior of said cylindrical wall.

17; Proportioning apparatus for effecting a combustible mixture of fuel and air for delivery to a burner or the like comprising an outer casting having a generally cylindrical wall defining an open-ended bore the rear end of which constitutes a discharge outlet for the air, .a limited circumferential extent of said wall being hollow to define an arcuate gas entry chamber partially encompassing said bore, there being a gas inlet in communication with said chamber, an inner ring-shaped casting the annular wall of which is hollow to define a gas outlet. chamber, said inner casting being closely nested within said bore and capable of limited rotational movement therein in either direction, a shutter plate extending across the forward end of the inner casting and movable with the latter, an end casting in the form of a ring secured to the forward end of said outer casting, a shutter plate extending across said ring, there being a pair of cooperating shutter openings in said shutter plates defining a variable air inlet for the apparatus, there being a row of circumferentially spaced gas inlet ports formed'in the cylindrical wall of the outer casing communicating with the gas entry chamber, there being an arcuate slot in the annular wall of said inner casting capable of selective progressive cumulative registry with said ports upon turning movement of the inner casting relative to the outer casting, said inner casting being movable betweena retracted position wherein said shutter openings are out of registry with each other and said ports are out of registry, with said slot, there'being a gas discharge opening in the cylindrical wall of said outer casting and an opening in said hollow annular wall establishing communication between said gas outlet chamber and the interior of said cylindrical wall.

18. Proportioning apparatus for the delivery of varying quantities of fuel and air constituents of a combustible mixture to a burner or the like comprising an outer casting having a generally cylindrical wall defining an open-ended bore the rear end of which constitutes a discharge outlet for at least one of saidconstituents, a limited circumferential extent of said wall being hollow to define an arcuate gas entry chamber partially encompassingsaid bore, there being a gas inlet in communication with said chamber, an inner ring-shaped casting the annular wall of which is hollow to define a gas outlet chamber, said inner casting being closely nested within said bore and capable of limited rotational movement therein in either direction, a shutter plate extending across the forward end .ofthe inner casting and movable with the latter, an end casting in the form of a ring secured to the forward end of said outer casting, a shutter plate extending across said ring, there being a pair of cooperating shutter openings in said shutter plates defining a variable air inlet for. the apparatus, there being a row of cirdrical wall of the outer casting communicating with the gas entry chamber, there being an arcuate slot in the annular wall of said inner casting capable of selective progressive cumulative registry with said ports upon turning movement of the inner casting relative to the outer casting, said inner casting being movable between a retracted position wherein said shutter openings are out of registry with each other and said ports are out of registry with said slot, and an advanced position wherein said shutters are in full registry and said ports are all in registry with said slot, there being an opening in the hollow wall of said inner casting constituting a gas discharge outlet from said gas outlet chamber.

19. Proportioning apparatus for etfecting a proportionate flow of gases issuing from two separate sources comprising an outer casing having a generally cylindrical wall defining an open-ended bore the rear'end of which constitutes a discharge outlet for at least one of said gases, a limited circumferential extent of said wall being hollow to define an arcuate entry chamber for one of said gases and partially encompassing said bore, there being an inlet for said one gas in communication with said chamber, an inner ring-shaped casing the annular wall of which is hollow to define an outlet chamber for said one gas, said inner casing being closely nested within said bore and capable of limited rotational movement therein in either direction, a shutter plate extending across the forward end of the inner casing and movable with plates defining. a variable inlet for the other gas, there being a series of circumferentially spaced inlet ports for said one gas formed in the cylindrical wall of the outer casing communicating with said arcuate entry chamber, there being an arcuate slot in the annular wall of said inner casing capable of selective progressive cumulative registry with said ports upon turning movement of the inner casing relative to the outer casing, said inner casing being movable between a retracted position wherein said shutter openings are out of registry with each other and said ports are out of registry with said arcuate slot, and an advanced position wherein said shutter openings are in full registry and said ports are in registry with said slot, there being a discharge opening in one wall of said inner casing, and an operating handle for said inner casing.

References Cited in the file of this pat ent UNITED STATES PATENTS 

